1. Field of the Invention
The present invention relates, in general, to an anti-frost device for refrigerators and, more particularly, to an anti-frost device provided with a heating means capable of preventing any frost from being formed at the outlet portion of a cool air distribution duct.
2. Description of the Prior Art
As well known to those skilled in the art, a refrigerator is used for preserving food and drink at cool temperatures for a lengthy period of time. Such a refrigerator comprises a refrigeration cycle system, which includes a condenser, compressor, capillary tube and evaporator and generates cool air. The cool air is distributed to all sides of the refrigerator.
FIG. 1 is a sectional view illustrating the construction and a cool air circulation of a refrigerator in accordance with the prior art.
As shown in the drawing, the typical refrigerator comprises a cabinet 1, opening at the front portion, and a door 3 hinged to a side wall of the cabinet 1. The cabinet 1 has a storing cavity 2, defined in the interior and used for preserving food and drink. In addition, the cavity 2 is typically divided into two compartments: freezer and refrigeration compartments.
With reference to FIG. 1, a cool air duct 6 is defined in the rear wall of the cabinet 1, while an evaporator 5 is mounted in the cool air duct 6. A plurality of first discharging holes 6a are formed at a partition wall between the cool air duct 6 and the cavity 2. A door duct 8 is provided in the door 3 and communicates with the cavity 2 through a plurality of second discharging holes 8a. Also, a cool air distribution duct 7 is provided in a side wall of the cabinet 1 and connects the cool air duct 6 to the door duct 8.
In FIG. 1, the reference numeral 3a denotes a gasket member, which is attached along the edge of the door 3 in order to prevent an unexpected leakage of cool air from the cavity 2 into the atmosphere or prevent an unexpected introduction of hot air from surroundings into the cavity 2 when the door 3 is closed. In addition, an anti-frost pipe 9 is set in the front edge of the cabinet 1. The above anti-frost pipe 9 allows high temperature refrigerant from the condenser to pass through, thus preventing the front edge of the cabinet 1 from being wet with dew in a high temperature and high humidity atmosphere.
The function of the above refrigerator will be described below.
As shown in FIG. 1, a liquid refrigerant, having low temperature and low pressure, is quickly vaporized in the evaporator 5 while absorbing heat from air in the cabinet 1, thus forming cool air to be circulated in the cabinet 1. The cool air is partially discharged from the duct 6 into the cavity 2 through the first discharging holes 6a and partially flows from the duct 6 into the distribution duct 7 as shown by the dotted arrow in FIG. 1. The cool air, introduced into the distribution duct 7, flows into the door duct 8 through the outlet of the distribution duct 7 prior to being discharged into the cavity 2 through the second discharging holes 8a.
However, the above refrigerator is problematic in that it is somewhat difficult for the cool air to smoothly circulate in the cabinet 1 due to frost formed at the outlet portion of the distribution duct 7, thus reducing the cooling efficiency of the refrigerator.
In a brief description, when the door 3 is opened, hot air flows from the atmosphere into the cavity 2 as shown by the solid arrow of FIG. 2, thus meeting the cool air, which has a low temperature less than that of the hot air. The inner surface of the cabinet 1 is thus wet with dew.
In particular, dewdrops are formed at the outlet portion of the distribution duct 7 because there is a wide temperature difference between the hot and cool air at the outlet portion of the distribution duct 7.
When the door 3 at the above position is closed, the temperature of the cavity 2 is dropped by a predetermined degree. Therefore, the dew, formed on the inner surface of the cabinet 1, turns into frost. Particularly, the dewdrops, formed at the outlet portion of the distribution duct 7, rapidly turn into frost during the circulation of cool air in the duct 7. When the door 3 is repeatedly opened and closed, such a frost formation is repeated, thus causing the outlet portion of the distribution duct 7 to be covered with frost.
It is thus difficult for cool air to smoothly circulate in the cavity 2, so the cooling efficiency of the refrigerator is reduced. Furthermore, in order to forcibly circulate the cool air, the cooling function of the refrigerator has to operate for extended periods of time, thus causing excessive electric power consumption.
In addition, such frost may be formed at the outlet portion of the cool air duct 6 or the door duct 8 as well as the distribution duct 7.